package JZOffer;

import java.util.Stack;

public class _5 {
    class Solution {
        Stack<Integer> stack1 = new Stack<Integer>();
        Stack<Integer> stack2 = new Stack<Integer>();

        public void push(int node) {
            stack1.push(node);
        }

        public int pop() {
            if (stack1.empty() && stack2.empty()) {
                throw new RuntimeException("Queue is empty");
            }
            if (stack2.empty()) {
                while (!stack1.empty()){
                    stack2.push(stack1.pop());
                }
            }
            return stack2.pop();
        }
    }

    Solution getSolution() {
        return new Solution();
    }

    public static void main(String args[]) {
        _5 c = new _5();
        _5.Solution s = c.getSolution();
        s.push(1);
        s.push(2);
        s.push(3);
        System.out.println(s.pop());
        System.out.println(s.pop());
    }
}
